Sensors and transducers transmit intelligence

Intelligent buildings

By Philippa Martin-King

There is a wide variety of intelligent applications in buildings that often simply goes unnoticed. Smart buildings get much of their intelligence from the small sensors and transducers that are integrated in their devices or simply added to already installed systems to track and transmit information that is vital to managing power and energy and helping curb consumption.

Tracking vital information. Tracking vital information.

Networked sensors provide intelligence

Today, much can be done to manage systems using sensors or transducers that are either built into equipment or simply installed peripherally around existing installations. Sensors can be used to detect, measure and estimate power consumption and needs. Using sensors that relay the information across a network to a computerized system that can analyze information and adjust power use accordingly, it is possible to cut down on electricity consumption for lighting, printers, computers and other such comforts that might otherwise remain unused but switched on for hours on end.

Tucked away in the heart of buildings

There are a wide variety of applications in buildings that often simply go unnoticed. For instance, in public buildings transducers can be installed in elevators, doors, and in lighting systems. More specific to manufacturing sites, there are transducers in most industrial drives: forklifts, machine tools, printing machines and power equipment. Today, most forklifts are battery-powered. It's transducers that control the precision and speed of the fork, calculating exactly the force that is necessary to lift the load. By optimizing the use of power, transducers are responsible for overall energy savings, since the batteries do not have to be charged up so frequently.

It's a transducer, too, that causes the door of an elevator to shut or to open again if it senses an obstacle. Then again in a high-rise building, a sensor will adjust the torque of the elevator so that it accelerates and stops smoothly at exactly the right level. Used intelligently, a transducer can be made to vary the speed drive of the electric elevator motor and thus economize energy.

Transducers can be retrofitted

A transducer is an electronic device that converts energy from one form to another. Dual element transducers with both sending and receiving elements are useful for measuring precisely either the flow of electric charge – the amps – or the electrical tension – the volts by quantifying the magnetic field on opposite sides of an electrical conductor through which an electric current is flowing, and transmitting the information elsewhere for analysis. Transducers can be installed as part of an electric circuit or, because they can be contactless, simply snapped over an existing cable with no need for modification, screwing or soldering. The implication is that they can be retrofitted very effectively into existing installations without having to shut down operations.

Transducers meter and monitor

A global company, LEM, reported in the March 2008 e-tech, designs and manufactures many of the world's transducers used for metering and monitoring devices as well as for industrial energy efficiency control. Originally, the company produced its transducers for electric trams where there was a need to ensure there was no interruption in power and that electricity supply was kept constant. Now, the devices are fast becoming an integral part of electronically controlled applications destined to improve energy efficiency. In buildings they control the safety of systems, monitor battery backup and track individual power consumption, both with a view to invoicing electricity consumption individually and to managing energy efficiency.

Tracking in real time

Thanks to their precision and the real-time measurements transducers and sensors can provide, it's easy to track the pattern of electricity usage and, in addition to controlling and monitoring consumption of individual residents or customers in a building, the measurements can provide sufficient stimulation to modify behaviour and, ultimately, to cut down energy use. At the same time, because the information is received in real-time, the Smart Grid is able to respond accurately to demand and take necessary measures to ease consumption during peak times and even out the load balance.

In a building, there are many types of basic measurements that can be made that involve voltage sensing, current sensing, temperature sensing, moisture sensing, continuity sensing and phase measurements. With the advent of wireless transmission capable of communicating data, it now makes economic sense to integrate sensors at all levels and to make use of that valuable information.

Standardizing the way forward

Many of the first sensor integration developments emerging on the market were built using nonstandard protocols that made their implementation difficult. A study produced by Mark Gaynor and Steve Boulton of Boston University on "Integrating Wireless Sensor Networks with the Grid" underlined how for a widespread adoption of wireless sensor technology applications, developers needed to have access to sensors with APIs (application programming interfaces) that their development environments supported.

Making the Smart Grid smarter

Now, with the plethora of applications appearing on the market, thanks to the technological developments of sensors, wireless networking and a standardized approach to transmitting, collecting and using the information, the Smart Grid can become smarter.

Taking a systems approach that accounts for even the smallest, most insignificant energy savings, finally, real economies of scale can be realized. The IEC and its various strategic groups and TCs have an important role to play in ensuring this is the case.

Transducers come in all shapes and sizes Transducers come in all shapes and sizes
Transducers can be added to an already installed system to track and transmit information Transducers can be added to an already installed system to track and transmit information
Tracking vital information. Tracking vital information.